Don Firth: at the time, not everybody and his pet chicken was trying to do it

Don, I would dearly love to have heard these chickens. Were they yokels?

Incidentally, Josepp, the person who is really qualified to teach music theory is the person who knows how to teach. No amount of knowledge, theoretical and/or practical, is of any use if the person putting it across is a poor teacher. My violin teacher - adept at both classical and traditional playing - is a wonderful teacher, capable of explaining concepts with clarity and, at the same time, always looking for the positive in one's playing.